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218Driving and operatingDeactivation
The system is deactivated by
pressing a; the LED in the button
extinguishes.
The system is deactivated
automatically when a trailer is
detected.
Fault
The system performance may be
affected by:
● Windscreen not clean or affected
by foreign items, e.g. stickers
● Close vehicles ahead
● Banked roads
● Winding or hilly roads
● Road edges
● Roads with poor lane markings
● Sudden lighting changes
● Adverse environmental conditions e.g. heavy rain or
snow
● Vehicle modifications, e.g. tyres.Switch off the system if the system is
disturbed by tar marks, shadows,
road cracks, temporary or
construction lane markings, or other
road imperfections.9 Warning
Always keep your attention on the
road and maintain proper vehicle
position within the lane, otherwise
vehicle damage, injury or death
could occur.
Lane keep assist does not
continuously steer the vehicle.
The system may not keep the
vehicle in the lane or give an alert,
even if a lane marking is detected.
The steering of the lane keep
assist may not be sufficient to
avoid a lane departure.
The system may not detect hands-
off driving due to external
influences (road condition and
surface, weather etc). The driver
has full responsibility to control the
vehicle and is always required to keep the hands on the steeringwheel while driving.
Using the system while towing a
trailer or on slippery roads could
cause loss of control of the vehicle
and a crash. Switch the system off.
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224Driving and operatingTrailer hitch
General information
Only use towing equipment that has
been approved for your vehicle.
Entrust retrofitting of towing
equipment to a workshop. It may be
necessary to make changes that
affect the cooling system, heat
shields or other equipment.
The bulb outage detection function for trailer brake light cannot detect a
partial bulb outage, e.g. in case of four
times five watt bulbs, the function only detects lamp outage when only a
single five Watt lamp remains or none
remain.
Fitting of towing equipment could
cover the opening of the towing eye.
If this is the case use the coupling ball bar for towing. Always keep the
coupling ball bar in the vehicle when
not in use.Driving characteristics and
towing tips
Before attaching a trailer, lubricatethe coupling ball. However, do not do
so if a stabiliser, which acts on the
coupling ball, is being used to reduce snaking movements.
During trailer towing do not exceed a
speed of 80 km/h. A maximum speed
of 100 km/h is only appropriate if an
oscillation damper is used and the
permissible gross trailer weight does
not exceed the vehicle’s curb weight.
For trailers with low driving stability
and caravan trailers, the use of an
oscillation damper is strongly
recommended.
If the trailer starts snaking, drive more
slowly, do not attempt to correct the
steering and brake sharply if
necessary.
When driving downhill, drive in the
same gear as if driving uphill and
drive at a similar speed.
Adjust tyre pressure to the value
specified for full load 3 295.Trailer towing
Trailer loadsThe permissible trailer loads are
vehicle and engine-dependent
maximum values which must not be
exceeded. The actual trailer load is the difference between the actual
gross weight of the trailer and the
actual coupling socket load with the
trailer coupled.
The permissible trailer loads are
specified in the vehicle documents. In
general, they are valid for gradients
up to 12%.
The permissible trailer load applies
up to the specified incline and at sea
level. Since engine power decreases
as altitude increases due to the air
becoming thinner, therefore reducing
climbing ability, the permissible gross train weight also decreases by 10%for every 1000 metres of altitude. The gross train weight does not have to be
reduced when driving on roads with
slight inclines (less than 8%, e.g.
motorways).
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Driving and operating225The permissible gross train weight
must not be exceeded. This weight is
specified on the identification plate
3 282.
Vertical coupling load
The vertical coupling load is the load
exerted by the trailer on the coupling
ball. It can be varied by changing the
weight distribution when loading the
trailer.
The maximum permissible vertical
coupling load (75 kg) is specified on
the towing equipment identification
plate and in the vehicle documents.
Always aim for the maximum load,
especially in the case of heavy
trailers. The vertical coupling load
should never fall below 25 kg.
Rear axle load
When the trailer is coupled and the
towing vehicle fully loaded, the
permissible rear axle load (see
identification plate or vehicle
documents) may be exceeded by
40 kg. If the permissible rear axle load is exceeded, a maximum speed of
100 km/h applies.Towing equipmentCaution
When operating without a trailer,
remove the coupling ball bar.
Stowage of coupling ball bar
The bag with the coupling ball bar is
stowed on the rear floor cover in the
load compartment.
Place the strap through the rear right
lashing eye, wrap around twice and
tighten the strap to secure the bag.
Illustration shows 5-door hatchback.
Illustration shows Sports Tourer.
Fitting the coupling ball bar
On Sports Tourer remove cover from
rear bumper by pushing.
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Driving and operating227Insert the tensioned coupling ball bar
in the opening and push firmly
upwards until it audibly engages.
The rotary handle snaps back into its
original position resting against the
coupling ball bar without a gap.9 Warning
Do not touch rotary handle during
insertion.
Lock the coupling ball bar by turning
the key to position e. Remove the key
and close the protective flap.
Eye for break-away stopping cable
Illustration shows 5-door hatchback.
Illustration shows Sports Tourer.
Attach breakaway stopping cable to eye.
Check that the coupling ball bar is
correctly installed
● Green marking on rotary knob must point towards green
marking on coupling ball bar.
● There must be no gap between the rotary handle and the
coupling ball bar.
● The coupling ball bar must be firmly engaged in the opening.
● The coupling ball bar must be locked and the key removed.9Warning
Towing a trailer is permitted only
when a coupling ball bar is fitted correctly. If the coupling ball bardoes not engage correctly, seekthe assistance of a workshop.
Dismounting the coupling ball bar
Page 230 of 317
228Driving and operatingOpen the protective flap and turn the
key to position c to unlock the
coupling ball bar.
Pull out rotary handle and turn
clockwise as far as it will go. Pull out coupling ball bar downwards.
Insert sealing plug in opening.
Fold away connecting socket.
On Sports Tourer insert cover into
rear bumper as shown in the
illustration.
Stow the coupling ball bar in the bag
and secure by fixing the strap through the rear right lashing eye. Wrap
around twice and tighten the strap to
secure the bag.
Trailer stability assist
If the system detects snaking
movements, engine power is reduced
and the vehicle/trailer combination is selectively braked until the snaking
ceases. While system is working keep
steering wheel as still as possible.
Trailer stability assist is a function of
the Electronic Stability Control 3 182.
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250Vehicle careNo.Circuit32DC transformer/LED display/
Electrical heater/Climate
control/Glow plug controller33Anti theft warning horn34Horn35Power outlet load compartment36Right high beam (Halogen)/
Right low beam (LED)37Left high beam (Halogen)38LED headlight/Automatic head‐
light range adjustment39Front fog light40Central Gateway Module41Water in fuel sensor/Water
pump42Manual headlight range adjust‐
ment43Fuel pump44Rear view camera/Inside rear
view mirror/Trailer moduleNo.Circuit45LED headlight left/Automatic
headlight range adjustment left46Instrument cluster47Steering column lock48Rear wiper49Outside rearview mirror50LED headlight right/Automatic
headlight range adjustment
right51Left low beam (LED)52Engine control module/Trans‐
mission control module53Diesel exhaust system54Windscreen wiper55Electrical rear seat folding56–57–
After having changed defective fuses,
close the fuse box cover and press
until it engages.
If the fuse box cover is not closed
correctly, malfunction may occur.
Instrument panel fuse boxThe fuse box is located behind a
cover.
Pull the cover on the left side to
remove.
Page 255 of 317
Vehicle care253No.Circuit1–2–3Trailer module4–5–6–7–8–9–10Service11–12Front seat heating (on vehicles
with alarm horn)13Rear seat heating (on vehicles
with alarm horn)14Ignition15Seat ventilation16Trailer outletNo.Circuit17Trailer outlet18–19–20–21–22–
After having changed defective fuses,
close the fuse box cover and press
until it engages.
Additional fuses are located near the
vehicle battery.
Page 281 of 317

Service and maintenance279Severe operating conditions exist if
one or more of the following
circumstances occur frequently: Cold
starting, stop and go operation, trailer operation, mountain driving, driving
on poor and sandy road surfaces,
increased air pollution, presence of
airborne sand and high dust content,
driving at high altitude and large
variations of temperature. Under
these severe operating conditions,
certain service work may be required more frequently than the regular
service interval.
The international service intervals are
valid for the countries which are not
listed in the European service
intervals.
Service display 3 107.
Confirmations Confirmation of service is recorded inthe Service and warranty booklet.
The date and mileage is completed
with the stamp and signature of the
servicing workshop.
Make sure that the Service and
warranty booklet is completed
correctly as continuous proof ofservice is essential if any warranty or
goodwill claims are to be met, and is
also a benefit when selling the
vehicle.Recommended fluids,
lubricants and parts
Recommended fluids and lubricants
Only use products that meet the
recommended specifications.9 Warning
Operating materials are
hazardous and could be
poisonous. Handle with care. Pay
attention to information given on
the containers.
Engine oil
Engine oil is identified by its quality
and its viscosity. Quality is more
important than viscosity when
selecting which engine oil to use. The oil quality ensures e.g. engine
cleanliness, wear protection and oil
aging control, whereas viscosity
grade gives information on the oil's
thickness over a temperature range.